The above noted parent applications related to inertial gas-liquid impactor separators for removing and coalescing liquid particles from a gas-liquid stream, including in engine crankcase ventilation separation applications, including closed crankcase ventilation (CCV) and open crankcase ventilation (OCV).
Inertial gas-liquid separators are known in the prior art. Liquid particles are removed from a gas-liquid stream by accelerating the stream or aerosol to high velocities through nozzles or orifices and directing same against an impactor, typically causing a sharp directional change, effecting the noted liquid separation. Such inertial impactors have various uses, including in oil separation applications for blowby gases from the crankcase of an internal combustion engine.
The present invention arose during continuing development efforts relating to the above noted parent inventions.
In one embodiment, a system is provided for separating oil from blowby gas of an internal combustion engine, including providing increased separation efficiency early in the life of the engine without suffering objectionably high pressure drop late in the life of the engine including end-of-life condition of the engine. As an engine wears, more blowby gas is created and the impactor in the inertial gas-liquid separator sees a larger flow and increased pressure from the crankcase. When this happens, the impactor actually begins to perform with higher efficiency, but also has a larger pressure drop. Standard impactors must be designed to meet this end-of-life condition in order not to produce too high of a pressure drop. This means the efficiency early in the life of the engine may not be optimized.
In one embodiment, multiple stages allow the impactor design to be optimized for several points in the life of the engine. For example, in one embodiment, the blowby gas is exposed to fewer nozzles in the beginning when pressure and flow are lower. As pressure increases, more stages are opened. This means that efficiency can be high from the beginning of life, and pressure drop is controlled as the engine wears. This embodiment provides improved performance by delivering a more consistent efficiency and pressure drop over the life of the engine. In one embodiment, the device has one impactor stage that is constantly open to blowby gas flow, and one or more stages that are opened with relief valves as pressure increases. In one preferred embodiment, only the constant stage impactor is open at the beginning-of-life of the engine, and all stages will be open by the end-of-life of the engine.
In another embodiment, an inertial gas-liquid separator is provided with variable orifice jet nozzle structure having a variable orifice area dependent upon axial movement of a plunger relative to a housing sleeve. The variable orifice jet nozzle structure may be used with or without the noted constantly open impactor stage of the above embodiment.